Offshore oil wells are difficult to operate safely and under environmentally sound conditions because of hazards involving the underwater situs. Thus, storms through high waves and uncontrollable floating ship, barges, and the like, can cause damage to surface platforms and associated rigging including the well casing which can cause leakage of oil and pollution of the water surface. Also downwell conditions can cause excessive pressures, blowouts and damage to riggings at underwater positions inaccessible and difficult to correct.
The capping and controlling of a runaway underwater well has been difficult, awkward and in some cases unsuccessful, resulting in large areas of water surface pollution by oil and loss of scarce fossil fuels.
Thus, this invention has an objective of improving the state of the art for offshore oil wells to resolve these problems, to prevent oil spill pollution, to recover oil leaking from offshore oil well sites into the water, and to facilitate control and repair of abnormal and damaged well conditions.
There have been prior issued U.S. patents relating to techniques for resolving some of these problems as represented by those briefly discussed hereinafter.
It has been known to provide protective hoods over wellhead sites in both normal and abnormal conditions to receive and recover oil and associated materials flowing from a well. Thus, J. R. Gignous U.S. Pat. No. 1,521,088-Dec. 20, 1924, provides a protecting vented housing structure permanently constructed over an oil wellhead for confinement of the well in case of accident or fire. Also portable protective hoods are known for use in smothering a runaway well and recovering oil therefrom as represented by F. Sieven et al. U.S. Pat. No. 1,859,606-May 24, 1932; F. N. Bell U.S. Pat. No. 739,377-Sept. 22, 1903; and C. S. Howe U.S. Pat. No. 1,830,061-Nov. 3, 1931.
Protective structures are also known for use in offshore locations to surround at least a part of the wellhead site and rigging as represented by E. E. Horton U.S. Pat. No. 3,703,207-Nov. 21, 1972; J. T. Rodgers U.S. Pat. No. 3,964,543-June 22, 1976; and W. Griesser U.S. Pat. No. 1,465,664-Aug. 21, 1923. These structures are erected at the well site both before drilling as in the latter patent and after the drilling is completed and the well is rigged.
Also of some interest is the technique of keeping the wellhead rigging under water as in R. B. Burns U.S. Pat. No. 3,866,676-Feb. 18, 1975.
The present invention has improved this state of the art by providing apparatus and procedures useful at offshore well sites to better facilitate offshore drilling, well servicing, protection from damage and handling of emergency conditions as will be described throughout the following description of the particular advances in the art.